Modular medical injection system

ABSTRACT

A medical injection system includes an elongate injection apparatus and an actuator apparatus. The actuator apparatus includes a fitting for coupling the actuator apparatus to a delivery catheter and a reversible gripping means to grip the injection apparatus; the gripping means is included in a plunger that is slideably engaged with the fitting and directs the injection apparatus through a fitting lumen and through a catheter lumen, when the fitting is coupled to the catheter.

TECHNICAL FIELD

The present invention relates generally to medical systems fordelivering therapeutic agents and more particularly to elements of amodular injection system.

BACKGROUND

Because a therapeutic agent, for example pharmacological, genetic, orbiological, may be ineffective or even toxic when deliveredsystemically, tools and methods for delivering therapeutic agentslocally, that is, to a targeted tissue site, have been developed.

Many state-of-the art steerable catheters have lumens through whichagents may be delivered. Rather than modifying state-of-the-artsteerable catheter designs to integrally incorporate specific deliverymechanisms, such as means to inject agents into a tissue site, it isdesirable to provide modular apparatuses, which can be coupled to any ofsuch state-of-the-art steerable catheters and which include desiredspecific delivery mechanisms.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are illustrative of particular embodiments of theinvention and therefore do not limit its scope, but are presented toassist in providing a proper understanding of the invention. Thedrawings are not to scale (unless so stated) and are intended for use inconjunction with the explanations in the following detailed description.The present invention will hereinafter be described in conjunction withthe appended drawings, wherein like numerals denote like elements, and:

FIG. 1 is a plan view of a modular medical injection system according toone embodiment of the present invention;

FIG. 2 is a perspective sectional view of an actuator apparatus andinjection apparatus of the system shown in FIG. 1;

FIG. 3 is a section view of another member of a modular injection systemaccording to one embodiment of the present invention;

FIG. 4 is a plan view of the injection apparatus shown in FIG. 1according to one embodiment of the present invention;

FIG. 5 is an enlarged detailed view of a portion of the injectionapparatus shown in FIG. 4 according to some embodiments of the presentinvention; and

FIGS. 6A-D are partial section views of distal portions of injectionapparatuses according to alternate embodiments of the present invention.

DETAILED DESCRIPTION

The following detailed description is exemplary in nature and is notintended to limit the scope, applicability, or configuration of theinvention in any way. Rather, the following description provides apractical illustration for implementing exemplary embodiments of theinvention.

FIG. 1 is a plan view of a modular medical injection system according toone embodiment of the present invention. FIG. 1 illustrates the systemincluding a delivery catheter 120 to which an actuator 100 is joined bymeans of a coupling or connector 12 terminating a distal end of anactuator fitting 104; a lumen (not shown), which extends through a shaft123 and a handle 122 of catheter 120 and through actuator 100, slideablyengages an injection apparatus 110 whose needle tip 114 is shownextending out from a catheter distal end 125. FIG. 1 further illustratesinjection apparatus 110 including an elongate shaft 112 and a fitting 3terminating a proximal end of shaft 112, fitting 3 being adapted tocouple injection apparatus 110 to a source, for example a syringe, forinjection of therapeutic agents from the source through a lumen 113(FIG. 4) of injection apparatus 110. According to the illustratedembodiment, actuator 100 further includes a plunger 105 slideablyengaged with fitting 104; plunger 105 includes a valve 11, forreversibly gripping shaft 112 of injection apparatus 110 so that when anoperator forces plunger 105 toward fitting 104 per arrow A, shaft 112,being gripped by valve 11, is forced distally through catheter 120 sothat needle tip 114 moves out from catheter distal end 125 to pierce atarget tissue site in proximity to distal end 125. FIG. 1 furtherillustrates plunger 105 and fitting 104 each including radiallyextending surfaces 5 and 4, respectively, to facilitate operatorhandling to perform this operation.

According to embodiments of the present invention, catheter 120 may beany delivery catheter, known to those skilled in the art, that includesa compatible coupling for connector 12, for example a luer coupling; butcatheter 120 is preferably selected from a group of steerable cathetersknown to those skilled in the art, for example those that would includemanipulator means incorporated into a handle, i.e. handle 122illustrated in FIG. 1, the manipulator means causing deflection ofcatheter shaft 123 to facilitate positioning of catheter distal end 125at the target tissue site.

FIG. 2 is a perspective sectional view of one embodiment of actuatorapparatus 100 and injection apparatus 110 of the system shown in FIG. 1.FIG. 2 illustrates injection apparatus 110 having been positioned withinactuator apparatus 100 by passing needle tip 114 (FIG. 1) into openedvalve 11, through lumens of plunger 105 and fitting 104, and then outthrough connector 12. According to an exemplary embodiment, molded rigidplastics, examples of which include polycarbonate, polyethylene andpolypropylene, form plunger 105 and fitting 104.

FIG. 2 further illustrates fitting 104 including a spring member 10,which is mounted at an interface between plunger 105 and fitting 104, aside port 14, which is terminated by a stop cock 13 and in fluidcommunication with the lumen of fitting 104, for flushing a lumen of acatheter to which fitting will be coupled, and a septum 7, which is heldin place by a septum cap 6, for sealing plunger 105 from the catheterlumen, while allowing passage of injection apparatus 110 therethrough.According to the illustrated embodiment, spring member 10 holds plunger9 in a retracted position until a force is applied to slide plunger 105distally with respect to fitting 104. When this force is applied, valve11, which is illustrated here as a Touhy-Borst type, will have beentightened, according to means known to those skilled in the art, suchthat internal walls of a compressible member 1 protrude into the lumenof plunger 105 to grip injection apparatus 110 so that injectionapparatus 110 is advanced distally along with plunger 105. It should benoted that the scope of the present invention covers other means forreversibly gripping injection apparatus 110 known to those skilled inthe art, examples of which include, but are not limited to, 3-jaw chucksand set screws. FIG. 2 further illustrates injection apparatus 110including a grip tube 9 positioned around shaft 112 (further illustratedin FIG. 4), which enlarges an outer diameter of shaft 112 to facilitategripping of injection apparatus 110 by valve 11; grip tube 9 may furtherenhance gripping by means of a corrugated or soft and/or tacky outersurface.

According to one embodiment of the present invention, an introducer 30as illustrated in section view in FIG. 3 is used to facilitate insertionof injection apparatus 110 through actuator apparatus 100. FIG. 3illustrates introducer 30 including an introducer shaft 34 coupled to anintroducer handle 32 and a lumen 36 extending through an entire lengthof introducer 30; according to one embodiment, a length of shaft 34 issufficient to extend within actuator apparatus 100 from connector 12through valve 11 (FIG. 2) so that lumen 36 may provide a smooth passagefor injection apparatus 110 through an entire length of actuator 100.According to one method, a first end 366 of introducer 30 would beinserted into actuator 100 at connector 12 and passed through actuator100 until first end 366 extends out from valve 11; then needle tip 114(FIG. 1) would be inserted into lumen 36 at first end 366 and passedthrough until tip 114 protrudes from a second end 362 of introducer 30;finally introducer 30 would be removed from actuator 100 and fitting 104may then be coupled to a catheter.

Returning now to FIG. 1, a method for advancing injection apparatus 110through catheter 123, according to one embodiment of the presentinvention, will be described. Upon coupling actuator 100 to catheter120, an operator may advance injection apparatus 110 through catheteruntil needle tip 114 is approximately flush with catheter distal end125, at which time valve 11 is closed to grip injection apparatus 110;thus, injection apparatus 110 is held in place within catheter 120 whilethe operator advances catheter 120 to a target tissue site. Once theoperator has positioned catheter distal tip 125 in close proximity tothe target site, the operator causes plunger 105 to advance distally,thereby pushing needle tip 114 of injection apparatus 110 into the site;either in conjunction with or following plunger action, a therapeuticagent is injected through injection apparatus 110 from a source oftherapeutic agent which is coupled to injection apparatus 110, viafitting 3. According to the embodiment illustrated in FIG. 2, actuatorapparatus 100 includes a stop in the form of a pin 8 extending intofitting 104 and interfacing with a depression 18 formed on plunger 105;the stop is designed to limit the plunger travel according to aprescribed injection depth. Finally, after injection of the therapeuticagent is completed, the operator allows plunger 105 to retract by meansof the spring force previously described.

FIG. 4 is a plan view of injection apparatus 110 according to oneembodiment of the present invention. FIG. 4 illustrates injectionapparatus 110 including a modified distal portion 40 of shaft 112;distal portion 40 extends from an end 44 of a proximal portion of shaft112 to a distal end 42 of shaft 112 and is modified for increasedflexibility relative to the proximal portion of shaft 112. FIG. 4further illustrates needle tip 114 extending from shaft distal end 42;according to some embodiments needle tip 114 is an independent member,which has been fixedly coupled to shaft 112 in proximity to distal end42. Examples of appropriate needle tips include, but are not limited to,20-25 gauge stainless steel tips.

Dashed lines in FIG. 4 indicate lumen 113 of shaft 112 extending frominjection apparatus fitting 3 to needle tip 114 and approximatelyaligned with a lumen 115 of needle tip; lumens 113, 115 are adapted todeliver therapeutic agents out through needle tip 114 when tip 114 hasbeen inserted into a target tissue site. Shaft may be formed from anyappropriate biocompatible material known to those skilled in the art,which has sufficient strength and rigidity to accommodate lumen 113 andto push needle tip 114 into a target tissue site; one such material isstainless steel, for example 304 or 316L stainless steel. Because apathway to a target tissue site may include a number of bends, which canbe more acute closer to the target site, modified distal portion 40decreases the inherent rigidity of shaft 112 over the length of distalportion 40 to improve tracking of injection apparatus 110 throughcatheter 120 to the target site.

FIG. 5 is an enlarged detailed view of distal portion 40 of injectionapparatus 110 according to some embodiments of the present invention.FIG. 5 illustrates distal portion 40 including a spiral cut extendingalong segments A, B and C; according to the illustrated embodiment apitch of spiral cut varies along portion 40 from a maximum or mostproximal pitch PP to a minimum pitch P1. FIG. 5 further illustratessegment C having an exponentially decreasing pitch from end 44 distally,segment B having a constant pitch, segment A having a linearlydecreasing pitch from P2 to P1, and a non-cut segment D terminatingsegment A. According to embodiments of the present invention, the spiralcut is formed through an entire wall thickness of shaft distal portion40. Appropriate methods for making the spiral cut are known to thoseskilled in the art, one example of which is laser cutting, and,according to preferred embodiments, a kerf width is betweenapproximately 0.015 mm and approximately 0.035 mm.

Examples of modified distal portion 40, included among embodiments ofthe present invention, are described in the following table: Segment CWherein pitch is blended Segment A exponentially Wherein pitchdecreasing Segment B decreases linearly from ˜4.9 mm to Wherein pitch is˜ from ˜0.75 mm ˜0.8 mm. constant. to ˜0.5 mm Example 1 Length ≅ 75 mm Length ≅ 40 mm  Length ≅ 3.75 mm Example 2 Length ≅ 100 mm Length ≅ 100mm Length ≅ 3.75 mm Example 3 Length ≅ 200 mm Length ≅ 100 mm Length ≅3.75 mm Example 4 Length ≅ 300 mm Length ≅ 100 mm Length ≅ 3.75 mmAccording to the exemplary embodiments, an overall length of injectionapparatus 110 is approximately 150 cm and an outer diameter is betweenapproximately 0.6 mm and approximately 0.7 mm.

FIGS. 6A-D are partial section views of distal portions of injectionapparatuses according to alternate embodiments of the present invention.FIG. 6A illustrates a needle tip 64 inserted into distal end 42 of shaft112 such that a proximal end 641 is in proximity to distal end 42, whileFIGS. 6B-C illustrate needle tips 640 and 604 that extend into shaft 112beneath an entire length of distal portion 40 such that tip proximalends 642 and 602, respectively, are positioned proximal to end 44.Needle tips 64, 640 and 604 may be formed of stainless steel, Nitinol,or any other appropriate needle material known to those skilled in theart.

According to the embodiment illustrated in FIG. 6A, needle tip 64 isfixedly coupled to shaft 112 by means of a joint 61, which may be formedby adhesive bonding, laser welding, mechanical crimping or any othersuitable means known to those skilled in the art. FIG. 6A furtherillustrates an outer layer 60 formed about distal portion 40; accordingto the spiral cut embodiments, layer 60 prevents leakage of therapeuticagents out through the cuts. Outer layer 60 may be extruded over distalportion 40 or, in the form of a previously extruded tube, fitted overportion 40 and bonded in place, for example with an adhesive or by laserenergy; examples of suitable materials for such outer layers include butare not limited to polyether block amides (PEBAX), polyurethanes,polyethylenes and silicones. According to alternate embodiments, outerlayer 60 is a tube, which has been fitted over distal portion 40 andheat shrunk into relatively tight conformance with an outer surface ofportion 40; examples of suitable materials for a shrink-fit outer layerinclude, but are not limited to, polyesters and fluoropolymers. One suchexemplary embodiment incorporates a polyester shrink tube, availablefrom Advanced Polymers of New Hampshire, having an inner diameter ofapproximately 0.029 inch and a wall thickness of approximately 0.00025inch. FIG. 6B illustrates an alternate embodiment in which outer layer60 is not included; rather a seal 65, for example made from siliconerubber, is positioned about an outer surface of needle tip 640, proximalto end 44, and engages an inner surface of shaft 112 to prevent passageof agents out through the spiral cuts of portion 40. FIG. 6B furtherillustrates needle tip 640 fixedly coupled to shaft by both joint 61 anda second joint 62.

FIG. 6C illustrates needle tip 604 tapering from proximal end 602 todistal end 601 wherein proximal end 602 is wedged within shaft 112. FIG.6C further illustrates outer layer 60 formed about portion 40 and ajoint 67 formed between needle tip 604 and shaft distal end 42.According to one embodiment, joint 67 solely fixedly couples tip 604 toshaft 112 and, according to another embodiment, joint 67 not onlycouples but further provides sealing between tip 604 and shaft distalend 42 (as illustrated by dashed lines), if proximal end 602 is notsealed within shaft. An adhesive backfill, a laser weld, or a mechanicalcrimp may form joint 67.

FIG. 6D illustrates an outer layer 605 extending over distal portion 40and over a portion of needle tip 640 just distal to shaft distal end 42;layer 605 may be formed in any manner similar to those described forlayer 60 and may be selected from the same group of materials. FIG. 6Dfurther illustrates a seal 650 positioned between needle tip 640 andouter layer 605. It should be noted that shorter needle tip 64,illustrated in FIG. 6A could be incorporated into this embodiment aswell.

In the foregoing detailed description the invention has been describedwith reference to specific embodiments. However, it may be appreciatedthat various modifications and changes can be made without departingfrom the scope of the invention as set forth in the appended claims.

1. A medical injection system, comprising: an elongate injectionapparatus comprising: an elongate shaft including a shaft lumenextending from a proximal end of the shaft to a distal end of the shaft;and a needle tip coupled to the shaft and extending distal to the distalend of the shaft, the needle tip including a needle lumen extendingtherethrough and approximately aligned with the shaft lumen; wherein theshaft lumen and the needle tip lumen provide a passage for injection oftherapeutic agents; and an actuator apparatus comprising: a fitting forcoupling the apparatus to a proximal portion of a delivery catheter, thefitting including a fitting lumen extending therethrough adapted toslideably receive the injection apparatus and to direct the injectionapparatus through a lumen of the catheter; and a plunger slideablyengaged with the fitting, the plunger including a plunger lumenextending therethrough adapted to slidably receive the injectionapparatus and to direct the injection apparatus through the fittinglumen; the plunger further including means for reversibly gripping theinjection apparatus within the plunger lumen; wherein the plunger slidesdistally and proximally with respect to the fitting to advance andretract, respectively, the injection apparatus within the catheter lumenwhen the actuator apparatus is coupled to the catheter and the grippingmeans grips the injection apparatus.
 2. The system of claim 1, whereinthe actuator apparatus further comprises a sealing means positionedbetween the plunger and the catheter lumen, the sealing means adapted toallow passage of the injection apparatus.
 3. The system of claim 1,wherein the actuator apparatus fitting further includes a side port influid communication with the fitting lumen for flushing the catheterlumen.
 4. The system of claim 1, wherein the actuator apparatus fittingfurther includes a male luer thread to couple with the catheter.
 5. Thesystem of claim 1, wherein the actuator apparatus further comprises aspring member mounted between the plunger and the fitting to hold theplunger in a retracted position until a force is applied to slide theplunger distally with respect to the fitting.
 6. The system of claim 1,wherein the means for reversibly gripping the injection apparatuscomprises a protrusion reversibly extending into the plunger lumen. 7.The system of claim 1, wherein the means for reversibly gripping theinjection apparatus comprises a Touhy-Borst valve.
 8. The system ofclaim 2, wherein the sealing means comprises an elastomeric plug mountedwithin the fitting lumen.
 9. The system of claim 2, further comprisingan introducer adapted for insertion through the fitting lumen and theplunger lumen of the actuator apparatus, the introducer including anadapter lumen extending therethrough to slideably receive the injectionapparatus, and wherein the injection apparatus is loaded into thefitting lumen and the plunger lumen of the apparatus by means of theintroducer, which is removed from the apparatus following loading. 10.The system of claim 1, further comprising an introducer adapted forinsertion through the fitting lumen and the plunger lumen, theintroducer including a lumen extending therethrough adapted to slideablyreceive the elongate member, and wherein the elongate member may beloaded into the fitting lumen and the plunger lumen of the apparatus bymeans of the introducer, which may be removed from the apparatusfollowing loading.
 11. The system of claim 1, wherein the shaft of theinjection apparatus further includes a proximal portion extending fromthe proximal end and a distal spiral cut portion extending distally fromthe proximal portion to the distal end of the shaft.
 12. The system ofclaim 11, wherein the needle tip of the injection apparatus furtherincludes a needle proximal portion, extending within the shaft lumen andterminated at a point proximal to the spiral cut portion.
 13. The systemof claim 12, wherein the needle tip is coupled to the shaft at aposition proximal to the spiral cut portion.
 14. The system of claim 12,wherein the injection apparatus further comprises a seal positionedabout an outer surface of the proximal portion of the needle tip andengaging an inner surface of the shaft proximal to the spiral cutportion in order to prevent a passage of the therapeutic agents from theshaft lumen out through the spiral cut portion.
 15. The system of claim11, wherein the injection apparatus further comprises an outer layerextending over the spiral cut portion.
 16. The system of claim 15,wherein the outer layer has a wall thickness less than or equal toapproximately 0.05 mm.
 17. The system of claim 15, wherein the outerlayer comprises a polymer.
 18. The system of claim 11, wherein thespiral cut portion of the injection apparatus has a length betweenapproximately 50 mm and 500 mm.
 19. The system of claim 11, wherein thespiral cut portion of the injection apparatus includes a length of adistally decreasing pitch.
 20. The system of claim 19, wherein thelength of distally decreasing pitch is between approximately 50 mm andapproximately 500 mm long.
 21. The system of claim 1, wherein theinjection apparatus further comprises a grip tube positioned about theshaft in proximity to the shaft proximal end; the grip tube facilitatinggripping by the gripping means included in the plunger of the actuatorapparatus.
 22. The system of claim 1, wherein the injection apparatusfurther includes a fitting coupled to the proximal end of the shaft, thefitting adapted to connect the shaft to a source for injection of thetherapeutic agents from the source through the injection apparatus. 23.A method for advancing a injection apparatus through a deliverycatheter, the method comprising the steps of: loading the injectionapparatus into a lumen of an actuator apparatus; coupling the actuatorapparatus to a proximal portion of the delivery catheter; advancing theinjection apparatus within a lumen of the delivery catheter; andtightening a gripping means of the actuator apparatus to grip theinjection apparatus within the apparatus.
 24. The method of claim 23,further comprising the step of pushing a plunger of the actuatorapparatus, in which the injection apparatus is gripped, to extend aneedle tip of the injection apparatus out from the catheter lumen at adistal end of the catheter.
 25. The method of claim 23, wherein loadingthe injection apparatus into the actuator apparatus comprises: insertingan introducer into the actuator apparatus, the introducer including alumen extending therethrough; inserting the injection apparatus into theintroducer lumen; and removing the introducer from the actuatorapparatus.
 26. An elongate medical injection apparatus, comprising: anelongate shaft including a lumen extending from a proximal end of theshaft to a distal end of the shaft, a shaft proximal portion extendingfrom the proximal end, and a shaft distal spiral cut portion extendingdistally from the shaft proximal portion to the distal end of the shaft;and a needle coupled to the shaft and including a lumen extendingtherethrough and approximately aligned with the shaft lumen, a needleproximal portion, extending within the shaft lumen and terminated at apoint proximal to the spiral cut portion, and a needle distal tipextending distal to the distal end of the shaft.
 27. The apparatus ofclaim 26, wherein the spiral cut portion has a length betweenapproximately 50 mm and 500 mm.
 28. The apparatus of claim 26, whereinthe spiral cut portion includes a length of a distally decreasing pitch.29. The apparatus of claim 28, wherein the length of distally decreasingpitch is between approximately 50 mm and approximately 500 mm long. 30.The apparatus of claim 26, further comprising an outer layer extendingover the spiral cut portion.
 31. The apparatus of claim 30, wherein theouter layer has a wall thickness less than or equal to approximately0.05 mm
 32. The apparatus of claim 30, wherein the outer layer comprisesa polymer.
 33. The apparatus of claim 32, wherein the polymer isselected from the group consisting of polyester shrink-fit andfluoropolymer shrink-fit.
 34. The apparatus of claim 30, wherein theouter layer further extends over a portion of the needle distal tip. 35.The apparatus of claim 34, further comprising a seal positioned betweenthe portion of the needle distal tip and the outer layer.
 36. Theapparatus of claim 26, wherein the needle is coupled to the shaft at aposition proximal to the spiral cut portion.
 37. The apparatus of claim26, further including a seal positioned about an outer surface of theproximal portion of the needle tip and engaging an inner surface of theshaft proximal to the spiral cut portion in order to prevent a passageof a therapeutic agent from the shaft lumen out through the spiral cutportion.
 38. The apparatus of claim 26, further comprising a fittingcoupled to the proximal end of the shaft, the fitting adapted to connectthe shaft to a source of therapeutic agent for injection of the agentfrom the source through the apparatus.
 39. An elongate medical injectionapparatus, comprising: an elongate shaft including a lumen extendingfrom a proximal end of the shaft to a distal end of the shaft, aproximal portion extending from the proximal end and a distal spiral cutportion extending distally from the proximal portion to the distal endof the shaft and including a length of a distally decreasing pitch; anda needle tip coupled to the shaft and extending distal to the distal endof the shaft, the needle tip including a lumen extending therethroughand approximately aligned with the shaft lumen; wherein the shaft lumenand the needle tip lumen provide a passage for injection of atherapeutic agent.
 40. The apparatus of claim 39, wherein the spiral cutportion further includes a maximum pitch of approximately 5 mm and aminimum pitch of approximately 0.5 mm.
 41. The apparatus of claim 39,wherein the distally decreasing pitch decreases exponentially.
 42. Theapparatus of claim 39, wherein the length of the distally decreasingpitch is between approximately 50 mm and approximately 500 mm long. 43.The apparatus of claim 42, wherein the length is between approximately100 mm and approximately 300 mm.
 44. The apparatus of claim 39, whereinthe spiral cut portion further includes a length of constant pitch. 45.The apparatus of claim 44, wherein the length of constant pitch extendsdistally from the length of decreasing pitch.
 46. The apparatus of claim44, wherein the constant pitch is less than or approximately equal to aminimum pitch of the length of distally decreasing pitch.
 47. Theapparatus of claim 44, wherein the length of constant pitch is betweenapproximately 40 mm and approximately 105 mm.
 48. The apparatus of claim39, wherein the distally decreasing pitch decreases linearly.
 49. Theapparatus of claim 41, wherein the spiral cut portion further includes alength of a linearly distally decreasing pitch.
 50. The apparatus ofclaim 49, wherein the length of linearly distally decreasing pitchextends to the distal end of the shaft.
 51. The apparatus of claim 49,wherein a maximum pitch of the linearly distally decreasing pitch isless than or approximately equal to a minimum pitch of the length ofdistally decreasing pitch.
 52. The apparatus of claim 51, wherein thelength of linearly distally decreasing pitch is between approximately 2mm and approximately 105 mm.
 53. The apparatus of claim 52, wherein thelength is between approximately 2 mm and approximately 5 mm.
 54. Theapparatus of claim 39, further comprising an outer layer extending overthe distal spiral cut portion.
 55. The apparatus of claim 54, whereinthe outer layer has a wall thickness less than or equal to approximately0.05 mm
 56. The apparatus of claim 54, wherein the outer layer comprisesa polymer.
 57. The apparatus of claim 56, wherein the polymer isselected from the group consisting of polyester shrink-fit andfluoropolymer shrink-fit.
 58. The apparatus of claim 54, wherein theouter layer further extends distal to the distal end of the shaft, overthe needle tip.
 59. The apparatus of claim 58, further comprising a sealpositioned between the outer layer and the needle tip.
 60. The apparatusof claim 39, wherein a proximal portion of the needle tip extends withinthe shaft and terminates at a point proximal to the spiral cut portion.61. The apparatus of claim 60, wherein the needle tip is coupled to theshaft at a position proximal to the spiral cut portion.
 62. Theapparatus of claim 60, further including a seal positioned about anouter surface of the proximal portion of the needle tip and engaging aninner surface of the shaft proximal to the spiral cut portion in orderto prevent a passage of the therapeutic agent from the shaft lumen outthrough the spiral cut portion.
 63. A medical actuator apparatus,comprising: a fitting for coupling the apparatus to a proximal portionof a delivery catheter, the fitting including a fitting lumen extendingtherethrough adapted to slideably receive an elongate member and todirect the elongate member through a lumen of the catheter; and aplunger slideably engaged with the fitting, the plunger including aplunger lumen extending therethrough adapted to slidably receive theelongate member and to direct the elongate member through the fittinglumen; the plunger further including means for reversibly gripping theelongate member within the plunger lumen; wherein the plunger slidesdistally with respect to the fitting to advance the elongate memberwithin the catheter lumen when the apparatus is coupled to the catheterand the gripping means grips the elongate member.
 64. The apparatus ofclaim 63, further comprising sealing means positioned between theplunger and the catheter lumen, the sealing means adapted to allowpassage of the elongate member therethrough.
 65. The apparatus of claim63, wherein the fitting further includes a side port in fluidcommunication with the fitting lumen for flushing the catheter lumen.66. The apparatus of claim 63, wherein the fitting further includes amale luer thread to couple with the catheter.
 67. The apparatus of claim63, further comprising a spring member mounted between the plunger andthe fitting to hold the plunger in a retracted position until a force isapplied to slide the plunger distally with respect to the fitting. 68.The apparatus of claim 63, wherein the means for reversibly gripping theelongate member comprises a protrusion reversibly extending into theplunger lumen.
 69. The apparatus of claim 63, wherein the means forreversibly gripping the elongate member comprises a Touhy-Borst valve.70. The apparatus of claim 63, wherein means for reversibly gripping theelongate member comprises a setscrew passing through a sidewall of theplunger and into the plunger lumen.
 71. The apparatus of claim 64,wherein the sealing means comprises an elastomeric plug mounted withinthe fitting lumen.
 72. The apparatus of claim 64, further comprising anintroducer adapted for insertion through the sealing means, theintroducer including an introducer lumen extending therethrough adaptedto slideably receive the elongate member, and wherein the elongatemember may be loaded into the fitting lumen and the plunger lumen of theapparatus by means of the introducer, which may be removed from theapparatus following loading.
 73. The apparatus of claim 63, furthercomprising an introducer adapted for insertion through the fitting lumenand the plunger lumen, the introducer including a lumen extendingtherethrough adapted to slideably receive the elongate member, andwherein the elongate member may be loaded into the fitting lumen and theplunger lumen of the apparatus by means of the introducer, which may beremoved from the apparatus following loading.
 74. A method for advancingan elongate member through a delivery catheter, the method comprisingthe steps of: loading the elongate member into a lumen of an actuatorapparatus; coupling the apparatus to a proximal portion of the deliverycatheter; advancing the elongate member within a lumen of the deliverycatheter; and tightening a gripping means of the apparatus to grip theelongate member within the apparatus.
 75. The method of claim 74,further comprising the step of pushing a plunger of the apparatus, inwhich the elongate member is gripped, to extend a distal portion of theelongate member out from the catheter lumen at a distal end of thecatheter.
 76. The method of claim 74, wherein loading the elongatemember into the apparatus comprises: inserting an introducer into theapparatus, the introducer including a lumen extending therethrough;inserting the elongate member into the introducer lumen; and removingthe introducer from the apparatus.